Sensor systems or camera systems are often used for monitoring areas relative to large commercial motor vehicles that are difficult or impossible for the driver of the vehicle to see, commonly known as blind spots. In the simplest case, a distance sensor is used for detecting the distance from the tail of the vehicle to the ramp. Typically, when approaching a ramp, the sensor transmits information regarding the distance to a receiver located in the driver cabin of the motor vehicle, which is then output on a display, providing the driver with a visual or auditory aid while reversing the vehicle.
Applicant's German Patent Application, System zur Ubertragung von Signalen in einem Kraftfahrzeug discloses the use of a video camera located on the tail of a motor vehicle for monitoring the rear areas of the vehicle. The image produced by the video camera is displayed on a monitor, enabling the driver of the vehicle to approach loading ramps in reverse, while recognizing, in real time, any obstacles behind the vehicle.
Typically, the system described in that application transmits the image signals from the camera via continuous wires generally made of copper, or also via fiber optic cable that are designated solely for the transmission of the signals generated by the camera. The installation of such additional signal wires, however, is time and cost intensive. Retrofitting vehicles with the wires necessary to transmit the camera signals is extremely difficult and can often only be realized at a high technical cost.
Further increasing the time and cost intensive nature of installing or retrofitting commercial vehicles with the additional signal wires is the fact that when dealing with commercial vehicles having a tractor and a trailer, it is essential that the trailer be detachable from the tractor towing it. Therefore, with respect to the signal wires running between the tractor and trailer, it must be possible to disconnect those signal wires.
In order to avoid this disadvantage, EP 1 273 478 proposes a wireless transmission of the image signals of the camera via radio signals. Control signals for the camera, such as swiveling, focusing, changing views, etc., can also be transmitted without wire. In such a transmission, however, other radio signals may interfere with the image created by the camera and/or control signals.
Often times, when two vehicles equipped with such a transmission system travel next to each other, such as during simultaneous approach of adjoining ramps for loading or unloading, the images displayed on the respective monitors of the two vehicles become distorted or are displayed on the wrong respective monitor, i.e. the image of a first vehicle is transmitted on the monitor of a second vehicle and visa versa.
It is therefore the object of the present invention to provide a system for transmitting signals in a motor vehicle that is flexible and insensitive to interference and can be easily retrofitted.